Resist stripping compositions and methods for manufacturing electrical devices

ABSTRACT

A liquid composition comprising (A) at least one polar organic solvent, selected from the group consisting of solvents exhibiting in the presence of from 0.06 to 4% by weight of dissolved tetramethylammonium hydroxide (B), the weight percentage being based on the complete weight of the respective test solution (AB), a constant removal rate at 50° C. for a 30 nm thick polymeric barrier anti-reflective layer containing deep UV absorbing chromophoric groups, (B) at least one quaternary ammonium hydroxide, and (C) at least one aromatic amine containing at least one primary amino group, a method for its preparation and a method for manufacturing electrical devices, employing the liquid composition as a resist stripping composition and its use for removing negative-tone and positive-tone photoresists and post etch residues in the manufacture of 3D Stacked Integrated Circuits and 3D Wafer Level Packagings by way of patterning Through Silicon Vias and/or by plating and bumping.

FIELD OF THE INVENTION

The present invention relates to new resist stripping compositionsuseful for removing patterned resists from substrates, in particularsemiconductor substrates, containing copper and low-k or ultra low-kmaterials.

Moreover, the present invention relates to new methods for manufacturingelectrical devices, in particular semiconductor integrated circuits(ICs), liquid crystal panels, organic electroluminescent panels, printedcircuit boards, micro machines, DNA chips and micro plants, especiallyICs, which new methods make use of the new resist strippingcompositions.

DESCRIPTION OF THE PRIOR ART

Resists such as deep UV photo resists or electron beam resists are usedin the microlithographic technique for producing a wide range ofelectrical devices, e.g. semiconductor integrated circuits (ICs), liquidcrystal panels, organic electroluminescent panels, printed circuitboards, micro machines, DNA chips and micro plants, in particular ICswith LSI (large-scale integration) or VLSI (very-large-scaleintegration).

Nowadays, copper is customarily used as the low electrical resistance orwiring material in the electrical devices, in particular in the vias andinterconnects contained in the ICs. The increasing use of copper and theever decreasing dimensions of the electrical structures together withthe ever increasing functionalities of the ICs require the use of low-kand ultra low-k materials in order to avoid problems with wiringresistance and wiring delay caused by high wiring capacities. Thesechallenging developments have demanded and still demand the continuingoptimization of the methods of manufacture and of the materials utilizedtherefore.

Upon forming a copper metal wiring, in particular, a process is used inwhich a copper multi-layer wiring is formed without etching copper byusing a dual damascene process. Owing to the low etching resistance ofcopper, various kinds of dual damascene processes have been proposed.One example thereof comprises the formation of a copper layer and theformation of a low-k layer (e.g., SiOC layer) on top of the copper layerfollowed by the formation of a resist layer as the uppermost layer.Optionally, a metal nitride layer (e.g., TiN layer) can be formed on topof the low-k layer before the resist layer is applied. In anothervariant, a barrier anti-reflective layer (BARC) is interposed betweenthe metal nitride layer and the resist layer.

Thereafter, the resist layer is selectively exposed to electromagneticradiation or electron beams and developed to form a resist pattern(“first photo resist pattern”). Then, by using the first resist patternas a mask pattern, the low-k or ultra low-k layer is partly dry-etchedby way of a fluorine containing plasma. The joint use of a metal nitridelayer in this process step is customarily designated as “hard masktechnique”. Thereafter, the first resist pattern is stripped away by anoxygen plasma ashing treatment. This way, wiring trenches are formed.

Next, another resist pattern (“second resist pattern”) is newly formedas the uppermost layer on the remaining multilayer structure, and theremaining low-k or ultra low-k layer is again partly etched away byusing the second photo resist pattern as a mask pattern, thereby formingthe via holes which communicate with the wiring trenches and the copperinterconnect wiring of the level below. Thereafter, the second photoresist pattern is also stripped away by oxygen plasma ashing treatment.

The wiring trenches and via holes are then filled with copper preferablyby electroplating, thereby creating multilayer copper wiring conductors.

The substrate for use in these processes may optionally be provided witha barrier layer (e.g., SiN layer or SiC layer) as an etch-stop layerbetween the copper layer and the low-k layer. In such a case, via holesand trenches are formed, and then, while the barrier layer exposed outon the substrate is kept as such or after the barrier layer has beenremoved, the photo resist is stripped away and, thereafter, the viaholes and the wiring trenches are filled with copper.

In the above described dual damascene process, silicon deposition mayreadily occur, resulting from the low-k layer during the etchingtreatment and the oxygen plasma ashing treatment for forming the viaholes on the trenches, and this may form silicon deposits around theopening of the trenches. In addition, a deposition that results from theresists may also occur. If these deposits are not completely removed,they can significantly decrease the yield in semiconductor production.

Accordingly, oxygen plasma ashing treatment has been used for theremoval of the resist patterns and etching residues in conventionalpatterning for metal wiring. However, the development ofultra-micropatterning technology, a material having a lower dielectricconstant, i.e. an ultra low-k material, must be used for the insulatinglow-k layer. At present, a process of using an ultra-low-k layer havinga dielectric constant of 3 or less has been developed. However, theultra low-k materials are poorly resistant or not resistant at all toashing. Consequently, a process not including an oxygen plasma ashingstep after etching must be employed, when such ultra-low-k materials areused.

To these end, so-called all-wet post-etch residue removal (PERR)processes have been developed and disclosed in the prior art.

The American patent application US 2003/0148624 A1 discloses a resiststripping composition for removing ashed and non-ashed resists, the saidcompositions containing quaternary ammonium hydroxides such astetramethylammonium hydroxide (TMAH), and organic solvents such asethanolamine, 1-amino-2-propanol, aminoethoxyethanol,1-methylaminoethanol, dimethyl sulfoxide, N-methylpyrrolidone,diethyleneglycol monomethyl ether, or diethylenglycol monobutyl ether.The examples specifically disclose a resist stripping compositionconsisting of 5% by weight ethanolamine, 50% by weight dimethylsulfoxide, 5% by weight propylene glycol, 0.05% by weight TMAH, 39.55%by weight of water, and 1 ppm or lower of dissolved oxygen, and a resiststripping composition consisting of 28% by weight 1-amino-2-propanol,62% by weight N-methylpyrrolidone, 1% by weight TMAH, 9% by weightwater, and 1 ppm of dissolved oxygen. These prior art resist strippingcompositions are used in the process wherein the resists have to bepre-cleaned with a particular cleaning composition containing 1% byweight or more of hydrogen peroxide and ammonia or ammonium ion.

The American patent application US 2004/0106531 A1 and the correspondingU.S. Pat. No. 7,250,391B2 disclose resist stripping compositionscontaining

(A) a salt of hydrofluoric acid and a base not containing a metal,(B1) a water-soluble organic solvent,(C) an acid selected from the group consisting of organic acids andinorganic acids, and(D) wateras the obligatory ingredients, and(E) an ammonium saltas an optional ingredient.

Ethanolamine, isopropanolamine, 2-(2-aminoethylamino)ethanol,N-methylethanolamine, N-ethylethanolamine, dicyclohexylamine, and TMAHmay be used as the base not containing a metal. The complete(A)-component is preferably used in an amount of from 0.01 to 1% byweight, based on the weight of the resist stripping composition. Whenused together with diphosphonic acid (C), the base not containing ametal can be used in an amount of from 0.1 to 20% by weight, based onthe weight of the resist stripping composition.

Diethyleneglycol monoethyl ether, diethyleneglycol monobutyl ether,N-methylpyrrolidone, and dimethyl sulfoxide can be used as thewater-soluble organic solvents (B).

The international patent application WO 2004/100245 A1 discloses aresist stripping composition comprising H₂SiF₆ and/or HBF₄, preferablyin an amount of from 0.001 to 5% by weight of the composition, anorganic solvent, preferably in an amount of from 50 to 89% by weight ofthe composition, optionally an amine, preferably in an amount of lessthan 1.5% by weight of the composition, a corrosion inhibitor,preferably in an amount of 0.001 to 10% by weight of the composition,and water as the balance. N-methylpyrrolidone, diethyleneglycolmonomethyl ether, or diethyleneglycol monobutyl ether can be used as theorganic solvent. Isopropanolamine, 2-(2-aminoethylamino)ethanol,2-(2-aminoethoxy)ethanol, and ethanolamine can be used as the optionalamine. TMAH is only used in a so-called high water embodiment which issubstantially free of organic solvents.

The related American patent applications US 2005/0176259 A1 and US2007/0298619 A1 disclose a resist stripping comprising a quaternaryammonium hydroxide such as TMAH, preferably an amount of from 1 to 20%by weight of the composition, water, preferably in an amount of from 5to 60% by weight of the composition, a water-soluble organic solvent,such as dimethyl sulfoxide, N-methylpyrrolidone, diethyleneglycolmonomethyl ether, diethyleneglycol monobutyl ether, and a water-solubleamine, such as ethanolamine, isopropanolamine, diethylenetriamine,2-(2-aminoethoxy)ethanol, or N-methylethanolamine, preferably in anamount of from 10 to 50% by weight of the composition. These prior artresist stripping compositions are used in a process wherein thepatterned resists have to be pretreated with ozone water and/or aqueoushydrogen peroxide before being stripped.

The American patent application US 2005/0014667 A1 and its correspondingpatent U.S. Pat. No. 7,399,365 B2 both disclose dilute aqueous resiststripping compositions comprising, for example, from 0.02 to 0.18% byweight of the composition of an ammonium fluoride, from 20 to 40% byweight of the composition of water, from 59 to 85% by weight of thecomposition of an amide and an ether solvent such as diethyleneglycolmonoethyl ether diethyleneglycol monobutyl ether andN-methylpyrrolidone, from 0.2 to 5% by weight of an acid, from 0.2 to 5%by weight of an alkanolamine such as ethanolamine, isopropanolamine,N-methylethanolamine, or 2-(2-aminoethylamino)ethanol, and from 0.2 to5% by weight of the composition of a quaternary ammonium compound suchas TMAH.

These prior art resist stripping compositions can be used for removingashed and non-ashed resists.

The related American patent applications US 2005/0266683 A1 and US2005/0263743 A1 both disclose a resist stripping composition comprisinga quaternary ammonium hydroxide such as TMAH, preferably in an amount offrom 1 to 30% by weight of the composition, water, preferably in anamount of from 15 to 94% by weight of the composition, an organic polarsolvent such as N-methylpyrrolidone, dimethyl sulfoxide,3-amino-1-propanol and ethanolamine, or mixtures thereof, preferably inan amount of from 25 to 85% by weight, and hydroxylamine or ahydroxylamine derivative, preferably in an amount of from 2 to 12% byweight of the composition. Allegedly, the use of an ashing stepemploying an oxygen plasma can be dispensed with.

The American patent application US 2006/0016785 A1 discloses aqueous andnon-aqueous resist stripping compositions for removing ashed andnon-ashed resists, the said compositions comprising from 0.5 to 15% byweight of the composition of a quaternary ammonium compound such as TMAHor tetrabutylammonium hydroxide (TBAH), an organic solvent such asdiethyleneglycol monomethyl ether or diethylene glycol monobutyl ether.

The Example K specifically discloses a resist stripping compositionconsisting of 65% by weight propyleneglycol methyl ether, 39% by weightpropyleneglycol propyl ether, 0.4% by weight water, 0.6% by weight TBAH,3% by weight p-toluenesulfonic acid, and 1% by weight ethanolamine. TheExample L specifically discloses a resist stripping composition beingfree of water and consisting of 56% by weight propyleneglycol propylether, 35.5% by weight propyleneglycol methyl ether, 0.5% by weightTBAH, 6% by weight p-toluenesulfonic acid, and 2% by weight ofethanolamine. The Example M specifically discloses a resist strippingcomposition consisting of 91.5% by weight propyleneglycol methyl ether,0.2% by weight water, 0.2% by weight TBAH 6% by weight p-toluenesulfonicacid, and 2% by weight ethanolamine. According to the Examples C, E, F,J, N, O, A5, P and S, TMAH is used in higher amounts ranging from 2.5%by weight to 5.5% by weight. According to the list of abbreviations usedin these Examples, both PGME and PGPE should mean propyleneglycol methylether. However, it is assumed that PGPE really means propyleneglycolpropyl ether.

The American patent application US 2008/0280452 A1 discloses a resiststripping composition for non-ashed resists having a high water contentand comprising a quaternary ammonium hydroxide such as TMAH, TBAH ormethyltripropylammonium hydroxide (MTPAH) preferably in an amount offrom 1 to 20% by weight of the composition, a water-soluble organicsolvent such as dimethyl sulfoxide and N-methylpyrrolidone, and awater-soluble amine such as ethanolamine, N-methylethanolamine and2-(2-aminoethoxy)ethanol, preferably in an amount of from 10 to 15% byweight of the composition. In particular, Table 2 discloses resiststripping compositions e.g. consisting of 10% by weight TMAH, 50% byweight dimethyl sulfoxide, and 40% by weight water (stripping solutionG), 5% by weight TBAH, 30% by weight N-methylpyrrolidone, 30% by weightdimethyl sulfoxide, and 25% by weight water (stripping solution J), or5% by weight MTPAH, 30% by weight dimethyl sulfoxide, 15% by weightN-methylpyrrolidone, 20% by weight water and 30% by weight2-(2-aminoethoxy)ethanol. However, for a complete removal of theresists, a pretreatment with ozone water and/or aqueous hydrogenperoxide is mandatory.

The resist stripping composition of the American patent application US2008/0280452 A1 can contain copper corrosion inhibitors selected fromthe group of aromatic hydroxy compounds such as p-aminophenol,m-aminophenol, diaminophenol and a minoresorcinol. Nothing is said as towhether these copper corrosion inhibitors can influence the resiststripping process in any way or that their use could render thepretreatment superfluous.

The prior art resist stripping compositions exhibit various drawbacksand disadvantages.

Thus, the resist stripping compositions containing N-methylpyrrolidoneprompt concerns over environment, health and safety (EHS).

Compositions having a high water content and/or a high quaternaryammonium hydroxide content can damage the low-k and, in particular, theultra low-k materials used in the modern IC technology. Due to thecomplexing and chelating power of hydroxylamine and hydroxylaminederivatives, the compositions containing these compounds can causecorrosion of copper vias and interconnects. Both effects can lead to apartial or a complete failure of the IC.

The removal rate for resists, post-etch residues (PER) and barrieranti-reflective layers (BARC) of resist stripping compositions having ahigh content of organic solvents strongly depends on the concentrationof the quaternary ammonium hydroxides. This strong dependence on theconcentration renders the optimization of the compositions difficult andcomplex. In particular, if high concentrations are required in order toachieve high removal rates, the aforementioned disadvantageous effectsare again obtained.

Quite often, the known resist stripping compositions exhibit differentremoval rates for unchanged resists on the one hand and the PER and theBARC on the other hand. In most cases, the PER and the BARC are muchmore difficult to remove than the unchanged resists. This is because thePER are having a chemical nature different from the resists and becausethe BARC are customarily highly cross-linked materials which are noteasy to dissolve or to disperse.

Moreover, the prior art resist stripping compositions may satisfactorilyremove the resists but exhibit unsatisfactory removal rates as far asthe etch residues, which have a complex composition and, inter alia,contain Teflon-like materials and titanium and/or silicon containingmaterials, are concerned.

Additionally, many processes utilizing prior art resist strippingcompositions require a pre-treatment step before the removal step. Quiteoften, ozone water and/or aqueous hydrogen peroxide is or are used.Apart from the concerns over EHS, these strongly oxidizing solutions candamage the low-k and ultra low-k materials, in particular thecarbon-doped silicon oxide (SiOC) materials by oxidizing the carbontherein contained.

Last but not least, the prior art processes require comparatively longprocess times in order to achieve a complete stripping off of thepatterned resists, the barrier anti-reflecting layers and the post-etchresidues without damaging the low-k or ultra low-k materials and/orover-etching the copper surfaces. If one attempts to shorten the processtimes, for example by increasing the contents of reactive ingredientssuch as quaternary ammonium hydroxides, fluorides or chelating agents,damage of the low-k or ultra low-k materialsand/or over-etching ofcopper surfaces result in many cases.

Three-dimensional (3D) technologies and architectures are becomingincreasingly important in the IC technology because they hold thepromise to further enable system performance increase in a time wheredevice skaling has become increasingly challenging.

For 3D applications, photoresists are employed for patterning throughsilicon vias (TSV) and also for plating and bumping (3D StackedIntegrated Circuit, 3D-SIC; 3D Wafer Level Packaging, 3D-WLP).

Customarily, few micrometer thick positive-tone photoresists are usedfor 3D-WLP TSV etch. A combination of dry silicon etch and wetphotoresist stripping is commonly used. In addition, negative-tonephotoresists can also be used as mold for copper plating andmicro-bumping applications. However, the prior art resist strippingcompositions are not always capable to remove both, negative-tone andpositive-tone photoresists, in the same manner.

Quite often, plasma damaged photoresist, i.e., post etch residues, PER,are difficult to remove. In order to get rid of such PER, theapplication of an additional physical force is often necessary.

For the 3D-WLP approach, the patterning of TSV and the micro-bumping isoften done on thinned silicon wafers which are bonded on carriers. Inthis case, the resist stripping compositions must also be compatiblewith the glue material.

In view of this, it would be highly desirable to have a resist strippingcomposition at hand which composition is capable of removingpositive-tone and negative-tone photoresists and PER in the same mostadvantageous manner without damaging blanket wafers surfaces, patternedwafer structures and the glue material bonding thinned silicon wafers oncarriers. However, the prior art photoresist strippers are not able orare only partially able to fulfill these challenging requirements.

OBJECTS OF THE INVENTION

Therefore, it has been the object of the present invention to providenew resist stripping compositions and new methods for manufacturingelectrical devices making use of the new resist stripping compositions,which compositions and methods no longer exhibit the drawbacks anddisadvantages of the prior art set out about above.

In particular, the new resist stripping compositions should no longercontain N-methylpyrrolidone, in order to dispense with theenvironmental, health and safety (EHS) problems caused by this solvent.

The new resist stripping compositions should no longer exhibit thedisadvantageous effects associated with a high water content and/or ahigh quaternary ammonium hydroxide content and should no longer damagethe low-k and, in particular, the ultra low-k materials used in themodern IC technology. In addition, the new resist stripping compositionsshould no longer contain hydroxylamine and hydroxylamine derivatives sothat the risk of the corrosion of copper vias and interconnects isminimized or, ideally, completely avoided.

The removal rate for resists, post-etch residues (PER) and barrieranti-reflective layers (BARC) of the new resist stripping compositionshaving a high content of organic solvents should no longer depend on theconcentration of the quaternary ammonium hydroxides. This way, theoptimization and the adaption of the new compositions to changingmanufacturing parameters should be rendered simple, straightforward andefficient, so that high concentrations are no longer required in orderto achieve high removal rates.

The new resist stripping compositions should exhibit the same oressentially the same removal rates for the unchanged resists on the onehand and the PER and the BARC on the other hand, so that the differentchemical nature of the PER and the BARC offers no longer an obstacle fortheir efficient removal.

Moreover, the new resist stripping compositions should not onlyexcellently remove the resists but also exhibit excellent removal ratesas far as the PER, which have a complex composition and containTeflon-like materials and titanium and/or silicon containing materials,are concerned.

Last but not least, the new resist stripping compositions shouldsignificantly shorten the process times required for a completestripping off of the patterned resists, the barrier anti-reflectinglayers and the post-etch residues without damaging the low-k or ultralow-k materials and/or over-etching the copper surfaces.

The new methods of manufacturing electrical devices, in particularsemiconductor integrated circuits (ICs), liquid crystal panels, organicelectroluminescent panels and printed circuit boards, micro machines,DNA chips and micro plants, especially ICs, utilizing the new resiststripping compositions should no longer require a pre-treatment stepbefore the removal step. In particular, the use of ozone water and/oraqueous hydrogen peroxide should be completely dispensed with so thatthe concerns over EHS associated therewith no longer exist and thedamage of the low-k and ultra-low-k materials by these stronglyoxidizing solutions can be avoided completely. On the whole, the newmethods of manufacture should yield flawless electrical devices whichare completely or essentially free from defects, exhibit an excellentfunctionality and have a long service life.

In addition to these objects, the new resist stripping compositionsshould be capable of being most advantageously used in 3D technologiesfor the manufacture of 3D architectures, in particular, in the field ofpatterning through silicon vias (TSV) and also for plating and bumping(3D Stacked Integrated Circuit, 3D-SIC; 3D Wafer Level Packaging,3D-WLP). In these applications, they should be capable of removingpositive-tone and negative-tone photoresists and PER in the same mostadvantageous manner without damaging blanket wafers surfaces, patternedwafer structures and the glue material bonding thinned silicon wafers oncarriers.

SUMMARY OF THE INVENTION

Accordingly, the novel liquid composition has been found, the saidcomposition comprising

-   (A) at least one polar organic solvent, selected from the group    consisting of solvents exhibiting in the presence of from 0.06 to 4%    by weight of dissolved tetramethylammonium hydroxide (B), the weight    percentage being based on the complete weight of the respective test    solution (AB), a constant removal rate at 50° C. for a 30 nm thick    polymeric barrier anti-reflective layer containing deep UV absorbing    chromophoric groups,-   (B) at least one quaternary ammonium hydroxide, and-   (C) at least one aromatic amine containing at least one primary    amino group.

Hereinafter, the novel liquid composition is designated as “compositionor compositions of the invention” as the case may be.

Additionally, the novel method for preparing a liquid composition hasbeen found, the said method comprising the steps of

-   (I) selecting at least one polar organic solvent (A) exhibiting in    the presence of from 0.06 to 4% by weight of dissolved    tetramethylammonium hydroxide (B), the weight percentage being based    on the complete weight of the respective test solution (AB), a    constant removal rate at 50° C. for a 30 nm thick polymeric barrier    anti-reflective layer containing deep UV absorbing chromophoric    groups,-   (II) mixing at least one of the selected polar organic solvents (A),    at least one quaternary ammonium hydroxide (B), and at least one    aromatic amine (C) containing at least one primary amino group.

Hereinafter, the novel method for preparing a liquid composition isreferred to as the “method of preparation of the invention”.

Moreover, the novel method for manufacturing electrical devices has beenfound, the said method comprising the steps of

-   (1) applying an insulating dielectric layer consisting of at least    one low-k or ultra-low-k material on top of a substrate,-   (2) applying a positive or a negative resist layer on top of the    insulating dielectric layer (1),-   (3) selectively exposing the resist layer to electromagnetic    radiation or corpuscular radiation,-   (4) developing the resist layer (3) to form a resist pattern,-   (5) dry-etching the insulating dielectric layer (1) using the resist    pattern (4) as a mask to form wire trenches and/or via holes    communicating with the substrate surface,-   (6) selecting at least one polar organic solvents (A) exhibiting in    the presence of from 0.06 to 4% by weight of dissolved    tetramethylammonium hydroxide (B), the weight percentage being based    on the complete weight of the respective test solution (AB), a    constant removal rate at 50° C. for a 30 nm thick polymeric barrier    anti-reflective layer containing deep UV absorbing chromophoric    groups,-   (7) providing at least one resist stripping composition comprising    -   (A) at least one polar organic solvent selected in accordance        with the process step (6),    -   (B) at least one quaternary ammonium hydroxide, and    -   (C) at least one aromatic amine (C) containing at least one        primary amino group,-   (8) removing the resist pattern and the post-etch residues by an    all-wet process using at least one resist stripping composition    prepared in accordance with the process step (7), and-   (9) filling the wire trenches and via holes with at least one    material having a low electrical resistivity.

Hereinafter, the novel method for manufacturing electrical devices isreferred to as the “manufacturing method of the invention”.

Additionally, the new use of a liquid composition for removingnegative-tone and positive-tone photoresists and post etch residues inthe manufacture of 3D Stacked Integrated Circuits and 3D Wafer LevelPackagings by way of patterning Through Silicon Vias and/or by platingand bumping has been found, the said composition comprising

-   (A) at least one polar organic solvent, selected from the group    consisting of solvents exhibiting in the presence of from 0.06 to 4%    by weight of dissolved tetramethylammonium hydroxide (B), the weight    percentage being based on the complete weight of the respective test    solution (AB), a constant removal rate at 50° C. for a 30 nm thick    polymeric barrier anti-reflective layer containing deep UV absorbing    chromophoric groups,-   (B) at least one quaternary ammonium hydroxide, and-   (C) at least one aromatic amine containing at least one primary    amino group.

Hereinafter, the new use of the liquid composition is referred to as the“use of the invention”.

ADVANTAGES OF THE INVENTION

In view of the prior art discussed above, it was surprising and couldnot be expected by the skilled artisan that the objects underlying thepresent invention could be solved by the composition of the invention,the preparation of the invention, and the manufacturing method of theinvention.

In particular, the compositions of the invention no longer containedN-alkylpyrrolidone, in particular, N-methylpyrrolidone, so that theenvironmental, health and safety (EHS) problems associated therewithwere no longer present.

The compositions of the invention no longer exhibited thedisadvantageous effects associated with a high water content and/or ahigh quaternary ammonium hydroxide content and no longer damaged thelow-k and, in particular, the ultra low-k materials used in the modernIC technology. In addition, the compositions of the invention no longercontained hydroxylamine and hydroxylamine derivatives so that the riskof the corrosion of copper vias and interconnects was considerablyminimized or, in many cases, completely avoided.

In the concentration range of from 0.06 to 4% by weight of thecomposition of the invention, the removal rate for resists, post-etchresidues (PER) and barrier anti-reflective layers (BARC) of thecompositions of the invention no longer depended on the concentration ofthe quaternary ammonium hydroxides. This way, the optimization and theadaption of the compositions of the invention to changing manufacturingparameters were rendered simple, straightforward and efficient, so thathigh concentrations of quaternary ammonium hydroxides were no longerrequired in order to achieve high removal rates.

The compositions of the invention exhibited the same or essentially thesame removal rates for the unchanged resists on the one hand and the PERand the BARC on the other hand, so that the different chemical nature ofthe PER and the BARC offered no longer an obstacle for their efficientremoval.

Moreover, the compositions of the invention did not only excellentlyremove the resists but also exhibited excellent removal rates as far asthe PER, which have a complex composition and contain Teflon-likematerials and titanium and/or silicon containing materials, wereconcerned.

Last but not least, the compositions of the invention significantlyshortened the process times required for a complete stripping off of thepatterned resists, the barrier anti-reflecting layers and the post-etchresidues without damaging the low-k or ultra low-k materials and/orover-etching copper surfaces.

On the whole, the compositions of the invention could be prepared,stored, handled and used without causing environmental, health andsafety (ESH) problems.

The method of preparation of the invention could be carried out in asimple, economical, safe and excellently reproducible way withoutcausing ESH-problems and did not require any particular and specialfacilities and safety measures. It yielded liquid compositions, inparticular compositions of the invention, which had excellentapplicational and property profiles

The manufacturing method of the invention for electrical devices, inparticular semiconductor integrated circuits (ICs), liquid crystalpanels, organic electroluminescent panels and printed circuit boards,micro machines, DNA chips and micro plants, especially ICs, no longerrequired a pre-treatment step before the removal step. In particular,the use of ozone water and/or aqueous hydrogen peroxide could becompletely dispensed with so that the concerns over EHS associatedtherewith no longer existed and the damage of the low-k and ultra-low-kmaterials by these strongly oxidizing solutions could be avoidedcompletely. On the whole, the manufacturing method of the inventionyielded electrical devices which were completely or essentially freefrom defects, exhibited excellent functionalities and had a long servicelife.

Furthermore, the compositions of the invention were most particularlysuited for the use of the invention in 3D technologies for themanufacture of 3D architectures, in particular, in the field ofpatterning through silicon vias (TSV) and also for plating and bumping(3D Stacked Integrated Circuit, 3D-SIC; 3D Wafer Level Packaging,3D-WLP). In these applications, they were capable of removingpositive-tone and negative-tone photoresists and PER very fast in thesame most advantageous manner without damaging blanket wafers surfaces,patterned wafer structures and the glue material bonding thinned siliconwafers on carriers.

DETAILED DESCRIPTION OF THE INVENTION

In its broadest aspect, the present invention is directed to a liquidcomposition containing the essential components (A), (B) and (C) ashereinafter described.

In the context of this invention, the characteristic “liquid” means thatthe composition of the invention is liquid at least at room temperature(i.e. 23° C.), preferably at least at 0° C. and most preferably at leastat −10° C.

The composition of the invention can be a dispersion, i.e. an emulsionor a suspension, or a homogeneous composition, wherein all theingredients are molecularly dispersed. Preferably, the composition ofthe invention is a homogeneous, molecularly dispersed composition.

The composition of the invention comprises at least one polar organicsolvent (A). For purposes of adapting the composition of the inventionto particular methods of manufacture of the invention, the compositioncan also contain two or more, in particular three, polar organicsolvents (A).

The polar organic solvents (A) can be aprotic or protic polar. Theamount of the at least one polar organic solvent (A) can vary broadlyand, therefore, can be adjusted most advantageously to the requirementsof a given method of manufacture of the invention. Preferably, thecomposition of the invention comprises, based on the complete weight ofthe composition, of from 40, more preferably of from 45 and mostpreferably of from 50% by weight to 99.95% by weight or, morepreferably, 99.94% by weight, of the at least two polar organic solvents(A).

When more than one polar organic solvent (A) are used in the compositionof the invention, the ratio of organic polar solvent (A1) to organicpolar solvent (A2) can also vary broadly and, therefore, can be adjustedmost advantageously to the requirements of a given method of manufactureof the invention. Preferably, the ratio (A1):(A2) is from 2:1 to 1:2,more preferably from 1.5:1 to 1:1.5, even more preferably from 1.3:1 to1:1.3 and most preferably from 1.1:1 to 1:1.1.

When more than two, e.g. three, four, five or n, organic polar solvents(A) are used in the composition of the invention, their ratio(A1):(A2):(A3):(A4):(A5), . . . and (An) can also vary broadly and,therefore, can also be adjusted most advantageously to the requirementsof a given method of manufacture of the invention. Preferably, the polarorganic solvents (A1), (A2), (A3), (A4), (A5), and (An) are used inequal or nearly equal amounts.

The at least one polar organic solvent (A) is selected from the groupconsisting of solvents which exhibit in the presence of dissolvedtetramethylammonium hydroxide (B) in an amount of from 0.06 to 4% byweight, based on the complete weight of the respective test solution(AB), at 50° C. a constant removal rate for a 30 nm thick polymericbarrier anti-reflective layer containing deep UV absorbing chromophoricgroups.

The characteristic “constant” means that, in the given range, theremoval rate is completely or virtually independent from theconcentration of the tetramethylammonium hydroxide (B).

For purposes of measuring the removal rate, the polymeric barrieranti-reflective layer is preferably applied onto a semiconductor wafersurface. Thereafter, the barrier anti-reflective layer on top of thesemiconductor wafer surface is exposed to test solutions (AB) oftetramethylammonium hydroxide (B) in the polar organic solvent (A) to betested having different concentrations of (B).

Preferably, tetramethylammonium hydroxide (B) is added as an aqueoussolution containing, based on the complete weight of the aqueoussolution, 25% by weight of tetramethylammonium hydroxide (B). Therefore,the test solutions (AB) can contain, based on the complete weight of thetest solution, up to 16% by weight of water (D).

Preferably, the test solutions (AB) are stirred during the tests at aconstant rotational speed, more preferably at 50 to 200 rpm, even morepreferably at 75 to 125 rpm and most preferably at 100 rpm.

In all the tests, the barrier anti-reflective layers on top of thesemiconductor wafer surfaces are exposed for the same time to the testsolutions (AB). Preferably, the exposure time is 180 s.

After the exposure, the semiconductor wafer pieces carrying the barrieranti-reflective layers are removed from the test solutions (AB), rinsedwith a polar organic solvent, preferably isopropanol, and, thereafter,with deionized water and dried with a dry non-reactive gas, preferablynitrogen. Most preferably, the rinsing and drying steps are carried outat moderate temperatures, preferably at temperatures of from 23 to 50°C.

After the drying step, it is examined by way of known and customaryspectroscopic methods whether the barrier anti-reflective layers arestill present. Preferably, transmission FTIR (Fourier TransformationIR-Spectroscopy) is used to this end.

In case that the barrier anti-reflective layers should still be present,their thickness is measured by way of known and customary methods formeasuring the thickness of thin layers. Preferably, transmission FTIRand/or interferometry is or are used to this end.

Most preferably, the barrier anti-reflective layers are completelyremoved during the exposure to the test solutions (AB).

For the selective tests described above, any known polymericanti-reflective coating compositions, as for example, those described inthe U.S. Pat. No. 5,919,599, column 3, line 40 to column 16, line 36 andcolumn 17, line 25 to column 18, line 25 in conjunction with the FIG. 1,can be used for preparing the polymeric barrier anti-reflective layerscontaining deep UV chromophoric groups.

As it is known in the art, that, due to their polymeric and cross-linkednature, the barrier anti-reflective layers are significantly moredifficult to remove than the patterned resists, the selective testsguarantee that the organic polar solvents (A) are selected such that thecompositions of the invention are even more so capable of completelyremoving the patterned resists and the post-etch residues together withthe barrier anti-reflective layers, most preferably within 180 s,without or essentially without redeposition.

Preferably, the polar organic solvents (A) are having a boiling point atatmospheric pressure above 100° C., more preferably above 120° C. andmost preferably above 150° C.

More preferably, the polar organic solvents (A) are having a flashpointas measured in a closed cup above 50° C., more preferably above 55° C.and most preferably above 60° C.

Most preferably, the at least two polar organic solvents (A) areselected from the group consisting of aliphatic polyamines comprising atleast two primary amino groups, aliphatic alkanolamines having at leastone carbon chain of at least 3 carbon atoms between one primary aminogroup and one hydroxyl group, aliphatic sulfoxides, and N-substitutedimidazoles. Particularly, the solvent (A) is selected from the groupconsisting of diethylenetriamine (boiling point 207° C., flashpoint 102°C.), N-methyl imidazole (boiling point 198° C., flashpoint 92° C.),3-amino-1-propanol (boiling point 187° C., flashpoint 101° C.),5-amino-1-pentanol (boiling point 222° C., flashpoint 65° C.), anddimethyl sulfoxide (boiling point 189° C., flashpoint 87° C.).

The composition of the invention furthermore comprises at least one,preferably one, quaternary ammonium hydroxide (B).

In the composition of the invention, the amounts of the quaternaryammonium hydroxide (B) can vary broadly and, therefore can be adjustedmost advantageously to the requirements of a given method of manufactureof the invention. Preferably, the composition of the inventioncomprises, based on the complete weight of the composition, of from 0.05to 10% by weight, more preferably of from 0.06 to 7% by weight, evenmore preferably of from 0.06 to 5% by weight, and most preferably 0.06to 1% by weight of at least one quaternary ammonium hydroxide (B).

Preferably, the quaternary ammonium hydroxide (B) is selected from thegroup consisting of tetramethylammonium, tetraethylammonium,tetrapropylammonium, tetrabutylammonium, benzyltrimethylammonium, and(2-hydroxyethyl)ammonium hydroxide, in particular tetramethylammoniumhydroxide.

The composition of the invention furthermore comprises at least one,preferably one, aromatic amine containing at least one, preferably one,primary amino group as the essential component (C).

In the context of the present invention “aromatic amine (C)” means thatno other reactive functional groups such as hydroxy groups, mercaptogroups, aldehyde groups, acid groups or acid halide groups are presentso that the amino groups, preferably the primary amino groups are theonly reactive functional groups present. Most preferably, the one aminogroup is the only reactive functional group present.

However, the aromatic amine (C) can contain non-reactive functionalgroup such as alkyl or cycloalkyl groups which may be halogenated ornot.

Preferably, the aromatic nucleus of the aromatic amine (C) does notcontain heteroatoms such as nitrogen or oxygen.

More preferably, the aromatic nucleus of the aromatic amine (C) canmonocyclic, i.e. a benzene ring, or polycyclic. The polycyclic aromaticnuclea can contain at least two benzene rings linked by a carbon-carbonbond, as for example in biphenyl or terphenyl, or at least two condensedbenzene rings, as for example in naphthalene or phenanthrene. Mostpreferably, a benzene ring is used.

Preferably, the aromatic amine (C) is selected from the group consistingof aniline, o-, m- and p-phenylenediamine, 2-, 3- and 4-aminobiphenyland 1- and 2-aminonaphthalene, with aniline being most preferably used.

In the composition of the invention, the amounts of the aromatic amine(C) can vary broadly and, therefore, can be adjusted most advantageouslyto the requirements of a given method of manufacture manufacture of theinvention. Preferably, the composition of the invention comprises, basedon the complete weight of the composition, of from 0.05 to 15% byweight, more preferably 0.1 to 10% by weight, and, most preferably, a0.1 to 5% by weight.

Additionally, the composition of the invention can be free of waterwhich means that the water content can also be so low as to beundetectable by known and customary methods for the qualitative andquantitative detection of water. Alternatively, the composition of theinvention may comprise water in various, preferably small, amounts asthe component (D). In this case, the water content is preferably <5% byweight, more preferably <4% by weight, even more preferably <3% byweight and most preferably <2% by weight, each weight percentage beingbased on the complete weight of the composition of the invention.

The composition of the invention can also contain at least oneadditional component selected from the group consisting of polar organicsolvents (E) different from the solvents (A), corrosion inhibitors (F)other than the aromatic amines (C) described hereinbefore, chelatingagents (G), fluoride salts (H), and surfactants (I).

Preferably, the polar organic solvent (E) is selected from the group ofsolvents exhibiting, in the presence of from 0.06 to 4% by weight ofdissolved tetramethylammonium hydroxide (B), the weight percentagesbeing based on the complete weight of the test solution (EB), a removalrate at 50° C. for a 30 nm thick polymeric barrier anti-reflective layercontaining deep UV absorbing chromophoric groups which increases withincreasing concentration of tetramethylammonium hydroxide (B).

Also here, tetramethylammonium hydroxide (B) is preferably added as anaqueous solution containing, based on the complete weight of the aqueoussolution, 25% by weight of tetramethylammonium hydroxide (B). Therefore,the test solutions (EB) can contain, based on the complete weight of thetest solution, up to 16% by weight of water (D).

The removal rates of the test solutions (EB) are determined in the sameway as described above for the test solutions (AB).

Preferably, the removal rates of the test solutions (EB) are 0 nm to 100nm under the conditions set out above at a concentration of 1% by weightof tetramethylammonium hydroxide (B), based on the complete weight ofthe test solution (DB).

Preferably, the polar organic solvents (E) are having a boiling point atatmospheric pressure above 100° C., more preferably above 120° C. andmost preferably above 150° C.

More preferably, the polar organic solvents (E) are having a flashpointas measured in a closed cup up 50° C., more preferably above 55° C. andmost preferably above 60° C.

Most preferably, the polar organic solvent (E) is selected from thegroup consisting of alkanol amines, alkylene glycol monoalkyl ethers,N-substituted piperidines, N-substituted cyclic ureas and N-substitutedimidazoles, particularly, ethanolamine (boiling point 172° C.,flashpoint 85° C.), N-methylethanolamine (boiling point 160° C.,flashpoint 72° C.), N-ethylethanolamine (boiling point 168° C.,flashpoint 78° C.), isopropanolamine (boiling point 159° C., flashpoint71° C.), 2-(2-aminoethylamino)ethanol (boiling point 243° C., flashpoint144° C.), 2-(2-aminoethoxy)ethanol (boiling point 223 to 242° C.,flashpoint 127° C.), diethyleneglycol monoethyl ether (boiling point193° C., flashpoint 93° C.), diethyleneglycol monobutyl ether (boilingpoint 230° C., flashpoint 107° C.), N-(2-hydroxyethyl)piperidine(boiling point 198 to 203° C., flashpoint 83° C.),1,3-dimethyl-3,4,5,6-tetrahydro-(1H)-pyrimidinone (boiling point 246°C., flashpoint 121° C.), N-(3-aminopropyl)imidazole (boiling point 296°C., flashpoint 154° C.), and dicyclohexylamine (boiling point 256° C.,flashpoint 105° C.).

The concentration of the polar solvent (E) in the composition of theinvention can vary broadly. However, the concentration should only be sohigh that the organic polar solvents (A) still mainly determines theproperty profile of the composition of the invention. Preferably, theweight ratio of the at least two polar organic solvents (A) to the polarorganic solvent (E) is in the range of from 5:1, more preferably 4:1and, even more preferably 3:1 and most preferably 2.5:1.

In principle, any known corrosion inhibitor (F) for metals can be used.Preferably, the corrosion inhibitor is selected from the groupconsisting of copper corrosion inhibitors (E), as described in forexample,

-   -   the international patent application WO 2004/100245 A1, page 9,        paragraph [0030] to page 10, paragraph [0031],    -   the American patent application US 2005/0176259 A1, page 4,        paragraph [0049] to page 5, paragraph [0059],    -   the American patent application US 2005/0263743 A1, page 5,        paragraph [0067] to page 6, paragraph [0073], and    -   the American patent application US 2008/0280452 A1, page 3,        paragraph [0045] to page 4, paragraph [0053].

The copper corrosion inhibitors (F) may be used in broadly varyingamounts. Preferably, they are used in the customary and effectiveamounts disclosed in the above-mentioned prior art.

In principle, any known chelating agent (G) can be used in thecomposition of the invention. Preferably, the chelating agent (G) isselected from the group of copper chelating agents (G), in particular,from the group of copper chelating agents (G) described in, for example,in the American patent applications

-   -   US 2004/0106531A1, page 6, paragraph [0074], and    -   US 2005/0263743 A1, page 5, paragraph [0070] to page 6,        paragraph [0073] in conjunction with paragraph [0078].

Quite often, such copper chelating agents (G) are also used as thecopper corrosion inhibitors (F).

The copper chelating agents (G) may be used in broadly varying amounts.Preferably, they are used in the customary and effective amountsdisclosed in the above-mentioned prior art.

In principle, any known fluoride salt (H) may be used in thecompositions of the intervention. Preferably, the fluoride salt (H) isselected from the group of salts of hydrofluoric acid and a base notcontaining a metal, as described in the American patent application US2004/0106531A1, page 3, paragraphs [0035] to [0041]. The fluoride salts(H) may be used in broadly varying amounts. Preferably, they are used inthe customary and effective amounts disclosed in the cited prior art, inparticular, in paragraph [0041].

In principle, any known surfactant (I) may be used in the composition ofthe invention. Preferably, the surfactant is selected from the group ofsurfactants as described in the American patent application US2008/0280452 A1, page 4, paragraph [0054] to page 5, paragraph [0061].The surfactants (I) may be used in broadly varying amounts. Preferably,they are used in the customary and effective amounts disclosed in thecited prior art, in particular, in paragraph [0061].

Preferably, the composition of the invention is free fromN-alkylpyrrolidones, in particular N-methylpyrrolidone andN-ethylpyrrolidone, as well as hydroxylamine and hydroxyl aminederivatives, in particular hydroxylamine derivatives as disclosed in theAmerican patent applications US 2005/0266683 A1, page 4, paragraphs[0046] to [0050], and US 2005/0263743 A1, page 4, paragraph [0057] topage 5, paragraph [0063].

In the context of this invention, the characteristic “free from” meansthat the relevant compounds cannot be detected in the composition of theinvention with the known state-of-the-art analytical methods forqualitatively and/or quantitatively detecting N-alkylpyrrolidoneshydroxylamine and hydroxylamine derivatives, e.g., gas chromatographyand/or mass spectrometry.

Preferably, the composition of the invention exhibits a dynamic shearviscosity at 50° C. as measured by rotational viscometry of from 1 to 10mPas, preferably 2 to 8 mPas, more preferably 1.5 to 7 mPas and mostpreferably 2 to 6 mPas. Preferably, the composition of the inventionalso exhibits a dynamic shear viscosity at 23° C. as measured byrotational viscometry of from 2 to 20 mPas, more preferably 3 to 16 mPasand most preferably 3 to 14 mPas.

The compositions of the invention can be prepared in various ways.Preferably, they are prepared according to the method of production ofthe invention. It is an advantage of the present invention that themethod of production of the invention can also be used for preparingother compositions than the compositions of the invention.

In the first process step of the method of production of the invention,at least one polar organic solvent (A) is selected as describedhereinbefore. Preferably, at least two and, more preferably, at leastthree polar organic solvents (A) are selected.

In the second process step of the method of production of the invention,at least two of the selected polar organic solvents (A) and at least onequaternary ammonium hydroxide (B) as described hereinbefore are mixedtogether.

At least one additional component selected from the group consisting ofpolar organic solvents (E) different from the solvents (A), corrosioninhibitors (F) other than the aromatic amines (C), chelating agents (G),fluoride salts (H), and surfactants (I) described hereinbefore can beadded in the first process step or in a separate process step preferablyin the preferred amounts disclosed in the cited prior art.

Preferably, the method of production of the invention is carried out inthe absence of the N-alkylpyrrolidones, hydroxylamine and hydroxylaminederivatives as described above.

In an additional process step of the method of production of theinvention, the shear viscosity at 50° C. of the mixture resulting fromthe second process step can be adjusted to 1 to 10 mPas, preferably 2 to8 mPas, more preferably 1.5 to 7 mPas and most preferably preferably 2to 6 mPas.

The additional process step can be carried out as a separate step or canbe integrated into each of the other process steps of the method ofproduction of the invention. The latter can be accomplished by carefullyselecting the ingredients for the second process step such that theresulting mixture exhibits the required dynamic viscosity.

Most preferably, the composition of the invention also exhibits adynamic shear viscosity at 23° C. as measured by rotational viscometryof from 2 to 20 mPas, more preferably 3 to 16 mPas and most preferably 3to 14 mPas.

Customary and standard mixing processes and mixing equipment such asagitated vessels, in-line dissolvers, high shear impellers, ultrasonicmixers, homogenizer nozzles or counterflow mixers can be used forcarrying out the mixing of the ingredients of the compositions, inparticular of the compositions of the invention.

The compositions of the invention, the composition prepared inaccordance with the method of production of the invention and, mostpreferably, the compositions of the invention prepared in accordancewith the method of production of the invention can be used for variouspurposes. In particular, they are used in the manufacturing method ofthe invention.

The manufacturing method of the invention yields most advantageouselectrical devices, in particular semiconductor integrated circuits(ICs), liquid crystal panels, organic electroluminescent panels, printedcircuit boards, micro machines, DNA chips and micro plants, especiallyhowever, ICs with LSI or VLSI.

The manufacturing method of the invention comprises the step of applyingan insulating dielectric layer consisting of at least one low-k orultra-low-k on top of a substrate in the first process step.

Suitable low-k or ultra-low-k materials and suitable methods ofpreparing the insulating dielectric layers are described in, forexample, the American patent applications US 2005/0176259 A1, page 2,paragraphs [0025] to [0027], US 2005/0014667 A1, page 1, paragraph[0003], US 2005/0266683 A1, page 1, paragraph [0003] and page 2,paragraph or US 2008/0280452 A1, paragraphs [0024] to [0026] or in theU.S. Pat. No. 7,250,391 B2, column 1, lines 49 to 54.

Suitable substrates are particularly semiconductor substratescustomarily used for the manufacture of ICs such as silicon wafers.

In the second process step, a positive or negative resist layer isapplied on top of the insulating dielectric layer.

Suitable materials and methods for preparing positive and negativeresist layers are described in, for example, the U.S. Pat. No.7,250,391B2, column 1, lines 55 to 60 or in the American patentapplications US 2005/0176259 A1, page 2, paragraphs [0029] and [0030],US 2006/0016785 A1, page 3, paragraphs [0025] to [0027] or US2008/0280452 A1, paragraphs [0027] to [0029] and page 5, paragraph[0062].

In the third step, the resist layer is selectivity exposed toelectromagnetic radiation or corpuscular radiation.

Preferably, UV-rays, deep UV-rays, excimer laser rays, in particular,KrF-, ArF- or F₂-excimer laser rays, or X-rays are used as theelectromagnetic radiation. For the exposure, the resist layer may beexposed to a light source capable of emitting such active rays, as forexample, low-pressure mercury lamps, high-pressure mercury lamps,ultra-high-pressure mercury lamps or xenon lamps, through a desired maskpattern.

The resist layer can also be directly exposed to corpuscular radiation,preferably, to electron beams.

Next, if desired, the resist pattern can be further baked (post-exposurebaking).

In the fourth process step, the selectively exposed resist layer isdeveloped with a developer, preferably an aqueous alkaline solution asdescribed in, for example, the American patent application US2008/0280452 A1, page 5, paragraph [0062], to yield the resist pattern.

In the fifth process step, the insulating dielectric layer is dry-etchedusing the resist pattern as a mask to form wire trenches and/or viaholes communicating with the surface of the layer below, such as thesurface of the substrate, the surface of the wiring of the level below,which wiring consists of at least one material having a low electricalresistivity, in particular copper or a copper alloy, or of the surfaceof an etch-stop layer, as for example, a silicon oxide nitride layer,interposed between the surface of the level below and the insulatingdielectric layer to be dry-etched. Preferably, a fluorine containingplasma, in particular, on the basis of a fluorocarbon gas is used as adry-etching agent.

In the dry-etching step, post-etch residues are generated, which must beremoved in the course of the BEOL (back-end of the line) process ofmanufacturing electrical devices. These post-etch residues can havevarying compositions comprising Teflon-like materials and titaniumand/or silicon containing materials.

In the sixth process step, at least two polar organic solvents (A) areselected as described hereinbefore.

In the seventh process step, the at least two selected polar organicsolvent (A) are used for preparing at least one, preferably one,composition of the invention as the resist stripping composition asdescribed hereinbefore.

In the eighth process step, the at least one, preferably one, resiststripping composition prepared in accordance with the seventh processstep is used for removing the resist pattern and the post-etch residuesby an all-wet process.

The efficiency of the resist stripping process step eight can beenhanced by irradiating the resist stripping solution with ultrasound.

Preferably, the eighth process step is carried out at temperatures offrom 0 to 70° C., more preferably 10 to 65° C. and most preferably 50 to60° C.

It is one of the major advantages of the manufacturing method of theinvention that, due to the use of the resist stripping composition ofthe invention, an ashing step, in particular, an ashing step using anoxygen containing plasma, or a pre-cleaning step, in particular, aprecleaning step using ozone water or hydrogen peroxide, can bedispensed with. Moreover, no or only very little redeposition ofhardened resist particles and/or post-etch residues can be observed.

After the stripping of the resist pattern and the post-etch residues,the resulting structure of wire trenches and/or via holes can be rinsed,in particular with deionized water, in order to remove any remainingresist stripping composition. Thereafter, the resulting structure can bedried, preferably with a dry non-reactive gas, in particular, nitrogen.

In the ninth process step, the wire trenches and via holes are filledwith at least one material having a low electrical resistivity.Preferably, copper and copper alloys, most preferably copper, is usedfor this purpose. Preferably, known copper electroplating solutions andelectroplating methods as, for example, described in the American patentapplication US 2006/0213780 A1 can be employed.

In the manufacturing process of the invention, a hard mask layer asdescribed in, for example, the U.S. Pat. No. 6,074,946 or U.S. Pat. No.6,218,078 B1 or the American patent applications US 2008/0286977 A1, US2008/10305441 A1, US 008/0305625 A1 or US 2009/0035944 A1 can be used.The said hard mask layer is selectively etched in the fifth process stepusing the resist pattern resulting from the fourth process step as themask.

Alternatively, a barrier anti-reflective layer as, for example,described in the American patent U.S. Pat. No. 5,919,599 can beinterposed between the resist layer and the insulating dielectric layer.Additionally, the barrier anti-reflective layer can also be interposedbetween the hard mask layer and the resist layer. In both cases, thebarrier anti-reflective layer is selectively etched in the fifth processstep using the resist pattern resulting from the fourth process step asthe mask, and is completely removed together with the patterned resistand the post-etch residues in the eighth process step.

After having carried out the manufacturing process of the invention, theresulting surface can be polished by chemical mechanical polishing (CMP)employing methods and equipment well-known in the art of manufacturingelectrical devices such as ICs. Thereafter, another layer of low-kdielectric material, optionally another hard mask layer, optionallyanother barrier anti-reflective layer, and, obligatorily, another resistlayer can be applied, whereafter the manufacturing process of theinvention is repeated.

The electrical devices prepared in accordance with the manufacturingmethod of the invention have an excellent functionality and a very longservice life.

One of the most surprising advantages of the compositions of theinvention is that, due to the high a boiling points of the organic polarsolvents (A) and the optional organic polar solvents (E) used, they allexhibit a low vapor pressure at medium temperatures, in particular, inthe temperature range of from room temperature up to 100° C. Moreover,due to the high flashpoints of the organic polar solvents (A) and theoptional organic polar solvents (E) used, all the compositions of theinvention are not readily flammable and not easily ignitable. Last butnot least, the organic polar solvents (A) and the optional organic polarsolvents (E) are not critical in terms of ESH. Therefore, this equallyapplies to compositions of the invention they are contained in.Consequently, the compositions of the invention can be prepared, stored,handled, used and disposed of without causing ESH problems.

An equally surprising advantage of the composition of the invention isthat it is particularly suitable for the use of the invention.

According to the use of the invention, the composition of the inventionis used for removing positive-tone and negative-tone resists as well asPER from blanket wafers and patterned wafers customarily used for themanufacture of 3D IC architectures which are also referred to as 3D-SICand 3D-WLP. In these 3D IC architectures the interconnects aremanufactured by way of TSV, plating and/or bumping, in particularmicro-bumping (cf. imec, Scientific Report 2008, Advanced Packaging andInterconnect, 3D Interconnect and Packaging, 3D Stacked IC (3D-SIC),3D-WLP: Micro-Bumping).

In the use of the invention, the composition of the invention is appliedto the photoresists and PER to be removed from blanket and patternedwafers by known and customary methods and equipment. After the removalof the photoresists, the wafers are rinsed and dried. The success of theremoval step, i.e., the complete absence of the photoresists ad PER, canbe confirmed by optical, scanning electron microscopy (X-SEM), atomicforce microscopy (AFM) and Fourier transform infrared (FTIR)spectroscopy inspection.

The compatibility of the composition of the invention with the gluematerial bonding thinned wafers on carriers, i.e., the presence ofundamaged glue material, can be confirmed by the same methods.

Most surprisingly, the composition of the invention is capable ofremoving positive-tone and negative-tone photoresists and PER from theblanket and patterned wafers fast and completely without damaging thefine structures of the patterned wafers or the glue materials present.

EXAMPLES Example 1 The Selection of Polar Organic Solvents (A)

The polar organic solvents listed in the Table 1 were preselectedaccording to their high boiling points, high flashpoints andenvironmental, health and safety (EHS) ratings (i.e., the solventsshould cause as little EHS problems as possible) from polar organicsolvents (S) from the group consisting of acid chlorides,chloroformates, alcohols, diols, polyols, aldehydes, acetals, ketones,amines, amino alcohols, carboxylic acids and derivatives, heterocycliccompounds, ionic liquids, nitriles, urea derivatives, vinyl compounds,vinyl ethers, and aliphatic amides.

TABLE 1 The Preselection of Polar Organic Solvents Flashpoint SolventBoiling (closed code Solvent point/° C. cup)/° C. S1 diethylenetriamine207 102 S2 N-methyl imidazole 198 92 S3 3-amino-1-propanol 187 101 S45-amino-1-pentanol 222 65 S5 dimethyl sulfoxide 189 87 S6N-(3-aminopropyl)imidazole 296 154 S7 2-(2-aminoethoxy)ethanol 223 to242 127 S8 N-ethylethanolamine 168 78 S9 N-methylethanolamine 160 72 S10ethanolamine 172 85 S11 isopropanolamine 159 71 S122-(2-aminoethylamino)ethanol 243 144 S13 N-(2-hydroxyethyl)piperidine198 to 203 83 S14 1,3-dimethyl-3,4,5,6-tetrahydro-(1H)- 246 121pyrimidinone S15 diethyleneglycol monobutyl ether 230 107 S16diethyleneglycol monoethyl ether 193 93 S17 dicyclohexylamine 256 105

For the final selection of the solvents (A) small pieces of siliconsemiconductor wafers were coated with 30 nm thick polymeric barrieranti-reflective layers containing deep UV absorbing chromophoric groups.The polymeric barrier anti-reflective layers were cross-linked.

Next, test solutions of tetramethylammonium hydroxide (TMAH) (B) in eachof the solvents (S) listed in the Table 1 were prepared. Each series oftest solutions (SB) consisted of seven solutions having TMAHconcentrations of 0.06, 0.1, 0.2, 0.5, 1.0, 2.0 and 4.0% by weight, theweight percentages being based on the complete weight of the respectivetest solution (SB), by adding the appropriate amounts of an aqueoussolution containing 25% by weight TMAH.

The removal rate of each of the test solutions (SB) of each series wasdetermined as follows:

A coated piece of the silicon semiconductor wafer was exposed in abeaker at 50° C. for 180 s to a test solution (SB) which was stirredwith 100 rpm. Thereafter, the coated piece of the silicon semiconductorwafer was removed from the test solution (SB), rinsed with isopropanoland then with deionized water and dried at 50° C. with a stream of drynitrogen. After cooling down to room temperature, it was investigated bytransmission FTIR and interferometry whether and, if yes, in whatthickness the cross-linked polymeric barrier anti-reflective layer wasstill present.

The Table 2 gives an overview over the results obtained.

TABLE 2 The Selection of Polar Organic Solvents (A) Removal rate: nmremoved at Solvent percent by weight TMAH: code 0.06 0.1 0.2 0.5 1.0 2.04.0 S1 30 30 30 30 30 30 30 S2 30 30 30 30 30 30 30 S3 30 30 30 30 30 3030 S4 30 30 30 30 30 30 30 S5 30 30 30 30 30 30 30 S6 0 0 0 0 0 7.5 30S7 0 0 0 0 0 30 30 S8 0 0 0 0 0 7.5 30 S9 0 0 0 0 0 17 30 S10 0 0 0 0 216 30 S11 0 0 0 0 9 16 30 S12 0 0 0 0 4 20 30 S13 0 0 0 0 5 15 30 S14 00 0 0 1 30 30 S15 0 0 0 0 4 15 30 S16 0 0 0 0 0 6 30 S17 0 0 0 0 23 1530

The test results presented in the Table 2 demonstrate that only theremoval rates of the solvents S1, S2, S3, S4, and S5 were independentfrom the TMAH concentration and that a complete removal of thecross-linked polymeric barrier anti-reflective layer could be achievedwith concentrations as low as 0.06% by weight based on the completeweight of the respective test solution. Consequently, only the solventsS1, S2, S3, S4, and S5 qualified as polar organic solvents (A) to beused in accordance with the invention. The other solvents (S) testedqualified however as optional polar organic solvents (E).

Example 2

The Influence of the TMAH Concentration of the Test Solutions (SB) onthe Etching Rate

Additionally, the compatibility of the test solutions (SB) containingthe polar organic solvents of Table 1 and 1% by weight, 2% by weight and4% by weight of TMAH, the weight percentages being based on the completeweight of the respective test solution, was tested as follows.

Pieces of silicon semiconductor wafers were coated with 400 nm thickultra low-k layers consisting of carbon-doped silicon oxide (BlackDiamond™ produced by Applied Materials, Inc.).

In order to evaluate the influence of the test solutions (SB) on theultra low-k layers, an untreated ultra low-k layer was annealed at 150°C. for 120 minutes as the reference point. If at all, the annealingcaused only very minimal changes of the thickness and of the refractiveindex.

The pieces of silicon semiconductor wafer coated with ultra low-k layerswere then exposed to the stirred (100 rpm) test solutions (SB) inbeakers at 50° C. for 180 seconds. Thereafter, the pieces were takenfrom the test solutions (SB), rinsed with isopropanol and water and thendried in a stream of dry nitrogen at 50° C. After cooling down to roomtemperature, the changes of the thickness of the ultra low-k layers andof the refractive index were measured:

Contrary to the untreated ultra low-k layer, almost all the exposedultra low-k layers exhibited a significant decrease in thickness, inparticular those layers which had been exposed to test solutions (SB)containing 2% by weight and 4% by weight of TMAH. After the testsolutions (SB) were removed from the exposed ultra low-k layers byannealing them at 150° C. for 120 minutes, the thickness decreased evenfurther, in particular, in the case of the layers which had been exposedto test solutions (SB) containing 2% by weight and 4% by weight of TMAH.

Contrary to the untreated ultra low-k layers, almost all the exposedultra low-k layers exhibited a significant increase of their refractiveindex, in particular those layers which had been exposed to testsolutions (SB) containing 2% by weight and 4% by weight of TMAH. Afterthe test solutions (SB) were removed from the exposed ultra low-k layersby annealing them at 150° C. for 120 minutes, the refractive indexincreased even further, in particular, in the case of the layers whichhad been exposed to test solutions (SB) containing 2% by weight and 4%by weight of TMAH.

These results demonstrated that high concentrations of TMAH led to asignificant damage of the ultra low-k material, due to the high etchingrate of the respective test solutions (SB).

No disadvantageous effects of this kind were observed, when the ultralow-k layers had been exposed to test solutions (SB) containing ≦0.5% byweight TMAH. In these cases, the etching rates were below 1 nm/minute.

The experiments were repeated with ultra low-k layers which had beenexposed to a fluorine containing etching plasma customarily used for theselective etching in order to produce the wire trenches and via holes.It turned out that the plasma damaged ultra low-k layers were even moreresistant to the test solutions (SB) containing ≦0.5% by weight TMAHthan the undamaged ultra low-k layer.

The experiments were repeated with pieces of copper disks. It turned outthat the test solutions (SB) containing ≦0.5% by weight TMAH exhibitedan etching rate below 1 nm/minute, whereas the test solutions (SB)containing more 1% by weight, 2% by weight and 4% by weight of TMAHexhibited much higher etching rates.

Similar results were obtained with tetrapropylammonium hydroxide,tetrabutylammonium hydroxide and benzyltrimethyl ammonium hydroxide. Thereactivity of these quaternary ammonium hydroxides is lower than TMAHand decreases in this order. This opens up the possibility offine-tuning the compositions and to adapt them to special manufacturingconditions in a simple manner.

To summarize, these findings further underline that compositionscontaining the polar organic solvents (A) selected in accordance withthe Example 1 and quaternary ammonium hydroxides, in particular TMAH, inlow concentrations are most particularly well suited and can be mostadvantageously used as resists stripping compositions for the removal ofpatterned photoresists, polymeric barrier anti-reflective layers andpost-etch residues in the back-and-of the line (BEOL) copper damasceneprocess for the manufacture of ICs with VLI and VLSI without damagingthe ultra-low-k materials or etching the copper surfaces.

Example 3

The Use of Compositions Containing a Polar Organic Solvent (A), TMAH (B)in Low Concentrations and Aniline (C) As Resists Stripping Compositions

300 mm silicon semiconductor wafers coated, in this order, with a 30 nmthick silicon carbide etch stop layer, a 386 nm thick ultra low-kcarbon-doped silicon oxide layer, a 39 nm thick titanium nitride hardmask layer, a 28 nm thick polymeric barrier anti-reflective layercontaining deep UV absorbing groups and a 60 nm thick layer of apositive 194 nm deep UV resist on the basis of a methacrylate copolymercontaining pending adamantane and lactone groups were used for theExample 3.

The coated silicon semiconductor wafers were selectively irradiated with194 nm deep UV radiation through test masks having various apertureswith dimensions below 100 nm, thereby solubilizing the exposed areas ofthe negative resist. Thereafter, the masks were removed and theirradiated resists layers were developed with an aqueous sodiumhydroxide solution to yield the desired resist patterns.

The upper surface of the coated silicon semiconductor wafers were thenexposed to a fluorine containing etching plasma using the patternedresists as the masks, thereby removing the areas of the polymericbarrier anti-reflective layers of the titanium nitride hard mask layersnot protected by the resist patterns. In this process step, theultra-low-k layers were not etched through but, at the most, only downto a small depth as compared with the complete thickness of the ultralow-k layers.

Resist stripping compositions were prepared by mixing the ingredients inthe desired amounts and homogenizing the resulting mixtures. Theingredients and their amounts are compiled in the Table 3. Thepercentages are given in percent by weight, based on the complete weightof the respective resists stripping composition. All resist strippingcompositions 3.1 to 3.5 of Table 3 had a dynamic viscositity at 50° C.as measured by rotational viscometry in the range of from 2 to 5 mPas.

TABLE 3 The Ingredients of the Resists Stripping Compositions and TheirAmounts (A) (B) (C) (D) Example Solvent TMAH Aniline Water No. Amount/%Amount/% Amount/% Amount/% 3.1 S1 98.7 0.06 1 0.24 3.2 S2 98.7 0.06 10.24 3.3 S3 98.7 0.06 1 0.24 3.4 S4 98.7 0.06 1 0.24 3.5 S5 98.7 0.06 10.24

Three series of the resists stripping compositions 3.1 to 3.5 of Table 3were used to remove the patterned resists, the patterned barrieranti-reflective layers and post-etch residues from the etched coatedsilicon semiconductor wafers. To this end, the wafers were placed intobeakers and exposed to the stirred (100 rpm) resists strippingcompositions at 50° C. in three series for 300 s, 180 s and 90 s.Thereafter, the wafers were taken from the resist strippingcompositions, rinsed with isopropanol and then with water and dried witha stream of dry nitrogen at 50° C. After cooling down to roomtemperature, the structures of the hard masks were inspected for defectswith AFM (atomic force microscopy) and SEM (scanning electronmicroscopy).

In all cases, the step heights of the patterned hard masks equalledexactly their original thickness even after 90 s only, demonstratingthat the resist stripping compositions had completely removed thepatterned resists, the patterned barrier anti-reflective layers andpost-etch residues without attacking the ultra low-k layers in anadvantageously short process time. The patterned hard masks reproducedexactly the structure of the test masks. No defects, deformations,irregular sidewalls, residues or redeposited materials could be observedwhich even more so underlined that the resist stripping compositionsexhibited an excellent cleaning power combined with an excellentcompatibility.

Example 4

The Use of Compositions Containing the Polar Organic Solvents (A) andTMAH in Low Concentrations for Stripping Positive-Tone and Negative-TonePhotoresists and Post-Etch Residues and the Compatibility of theCompositions with Glue Materials Bonding Thinned Silicon Wafers onCarriers

The compositions 3.1 to 3.5 of the Example 3 were used for carrying outthe Exampled 4.

Blanket silicon wafer pieces coated with commercially availablepositive-tone resist or negative-tone resist layers having a thicknessof 3.5 μm, 7 μm and 5 μm, respectively were exposed to the compositions3.1 to 3.82 at 65° C. for 5 minutes in beakers. They were subsequentlyrinsed with de-ionized water for 3 minutes and dried using a nitrogengun.

The compatibility with glue materials was checked in the same way.

It could be confirmed by optical inspection and FTIR spectroscopy thatthe resists were completely removed from the blanket silicon wafers. Onthe other hand, the glue materials were not attacked by the compositions3.1 to 3.5.

The removal of positive-tone photoresists, negative-tone photoresist andpost-etch residues from patterned silicon wafer pieces having coppermicro-bumps, copper plating and TSV was tested in the same way. It couldbe confirmed by X-SEM that the compositions 3.1 to 3.5 were capable ofcompletely removing the photoresists and residues without damaging thefine structures.

1. A liquid composition, comprising (A) a polar organic solvent, (B) aquaternary ammonium hydroxide, and (C) an aromatic amine comprising aprimary amino group, wherein the polar organic solvent (A) is at leastone selected from the group consisting of a solvent exhibiting aconstant removal rate at 50° C. in the presence of from 0.06 to 4% byweight of dissolved tetramethylammonium hydroxide (B), for a 30 nm thickpolymeric barrier anti-reflective layer comprising a deep UV absorbingchromophoric group, based on a total weight of a test solution (AB)comprising the polar organic solvent (A) and the tetramethylammoniumhydroxide (B).
 2. The liquid composition of claim 1, wherein thecomposition is free from N-alkylpyrrolidones, hydroxyl amine, andhydroxylamine derivatives.
 3. The liquid composition of claim 1, whereinthe aromatic amine (C) comprises one primary amino group as the onlyfunctional group.
 4. The liquid composition of claim 3, wherein thearomatic amine (C) is aniline.
 5. The liquid composition of claim 1,wherein the composition exhibits a dynamic shear viscosity at 50° C., asmeasured by rotational viscometry, of from 1 to 10 mPas.
 6. The liquidcomposition of claim 1, wherein at least two polar organic solvents (A)are selected such that the barrier anti-reflective layer is removablewithin 90 s.
 7. The liquid composition of claim 1, wherein the polarorganic solvent (A) exhibits a boiling point above 100° C.
 8. The liquidcomposition of claim 7, wherein the polar organic solvent (A) exhibits aflashpoint above 50° C., as measured in a closed cup.
 9. The liquidcomposition of claim 1, wherein the solvent (A) is at least one selectedfrom the group consisting of an aliphatic polyamine comprising at leasttwo primary amino groups, an aliphatic alkanolamine having at least onecarbon chain of at least 3 carbon atoms between one primary amino groupand one hydroxyl group, an aliphatic sulfoxide, and an N-substitutedimidazole.
 10. The liquid composition of claim 9, wherein the solvent(A) is at least one selected from the group consisting ofdiethylenetriamine, N-methyl imidazole, 3-amino-1-propanol,5-amino-1-pentanol, and dimethyl sulfoxide.
 11. The liquid compositionto of claim 1, wherein the quaternary ammonium hydroxide (B) is at leastone selected from the group consisting of tetramethylammonium,tetraethylammonium, tetrapropylammonium, tetrabutylammonium,benzyltrimethylammonium, and (2-hydroxyethyl)ammonium hydroxide.
 12. Theliquid composition to of claim 11, wherein the quaternary ammoniumhydroxide (B) is tetramethylammonium hydroxide.
 13. The liquidcomposition of claim 1, wherein the composition comprises at least oneadditional component selected from the group consisting of water (D), anadditional polar organic solvent (E) different from the polar organicsolvent (A), a corrosion inhibitor (F) different from the aromatic amine(C), a chelating agent (G), a fluoride salt (H), and a surfactant (I).14. The liquid composition of claim 13, wherein the additional polarorganic solvent (E) is at least one selected from the group consistingof a solvent exhibiting a removal rate at 50° C. that increases withincreasing concentration of tetramethylammonium hydroxide (B), for a 30nm thick polymeric barrier anti-reflective layer comprising a deep UVabsorbing chromophoric group, in the presence of from 0.06 to 4% byweight of dissolved tetramethylammonium hydroxide (B), wherein theweight percentage is based on the total weight of a respective testsolution (EB) comprising the additional polar organic solvent (E) andthe tetramethylammonium hydroxide (B).
 15. The liquid composition ofclaim 14, wherein the additional polar organic solvent (E) is at leastone selected from the group consisting of ethanolamine,N-methylethanolamine, N-ethylethanolamine, isopropanolamine,2-(2-aminoethylamino)ethanol, 2-(2-aminoethoxy)ethanol, diethyleneglycol monoethyl ether, diethylene glycol monobutyl ether,N-(2-hydroxyethyl)piperidine,1,3-dimethyl-3,4,5,6-tetrahydro-2-(1H)-pyrimidinone, andN-(3-aminopropyl)imidazole.
 16. The liquid composition of claim 13,wherein the corrosion inhibitor (F) is at least one copper corrosioninhibitor.
 17. A method for preparing the liquid composition of claim 1,the method comprising mixing at least one polar organic solvent (A), atleast one quaternary ammonium hydroxide (B), and at least one aromaticamine (C) comprising a primary amino group, to form a mixture.
 18. Themethod of claim 17, further comprising adjusting the dynamic shearviscosity at 50° C. of the mixture to 1 to 10 mPas, as measured byrotational viscometry.
 19. The method of claim 17, wherein the mixtureis free from N-alkylpyrrolidone; hydroxyl amine; and hydroxylaminederivatives.
 20. (canceled)
 21. A method, comprising: (1) applying aninsulating dielectric layer consisting of at least one low-k orultra-low-k material on top of a substrate; (2) applying a positive or anegative resist layer on top of the insulating dielectric layer (1); (3)selectively exposing the resist layer (2) to electromagnetic radiationor corpuscular radiation; (4) developing the selectively exposed resistlayer (3) to form a resist pattern; (5) dry-etching the insulatingdielectric layer (1) using the resist pattern (4) as a mask to form wiretrenches and/or via holes communicating with a substrate surface; (6)removing the resist pattern (4) and post-etch residues by an all-wetprocess with at least one resist stripping composition prepared by themethod of claim 17; and (7) filling the wire trenches (5) and via holes(5) with at least one material having a low electrical resistivity. 22.(canceled)
 23. The method of claim 21, wherein a hard mask layer (8) isinterposed between the resist layer (2) and the insulating dielectriclayer (1), and the hard mask layer (8) is selectively etched using theresist pattern (4) as the mask in the dry-etching (5).
 24. The method ofclaim 21, wherein a barrier anti-reflective layer (9) is interposedbetween the resist layer (2) and the insulating dielectric layer (1),and the barrier anti-reflective layer (9) is selectively etched usingthe resist pattern (4) as the mask in the dry-etching (5).
 25. Themethod of claim 23, wherein a barrier anti-reflective layer 9 isinterposed between the hard mask layer (8) and the resist layer (2), andthe barrier anti-reflective layer (9) and the hard mask layer (8) areselectively etched in the dry-etching (5).
 26. The method of claim 24,wherein the selectively-etched barrier anti-reflective layer (9) isremoved in the all-wet process (8).
 27. The method of claim 25, whereinthe selectively-etched barrier anti-reflective layer (9) is removed inthe all-wet process (8).
 28. The method of claim 21, copper is thematerial (7) having a low electrical resistivity.
 29. The method ofclaim 21, wherein the method is suitable for manufacturing electricaldevices selected from the group consisting of a semiconductor integratedcircuit, a liquid crystal panel, an organic electroluminescent panel, aprinted circuit board, a micro machine, a DNA chip and a micro plant.30. A method of manufacturing, comprising removing negative-tone andpositive-tone photoresists and post etch residues with the liquidcomposition of claim 1.